Improvement in lifting-jacks



H. H. LAWRENCE.

Lifting-lacks.

Patented March 11.`1874.

NITED STATES EEroE,

PATENT HENRY H. LAWRENCE, OF MAYWOOD, ILLINOIS, ASSIGNOR OF ONE-FOURTH HIS EIGHT 'IO ASA LAWRENCE, OF SAME PLACE.

IMPROVEMENT IN LlFTlNG-JACKS.

Spfcication forming part of Letters Patent No. l', dated March 17, 1874; application led February 24, 1874.

To all whom it may concern:

Be it known that I, HENRY H. LAWRENCE, ot' Maywood, in the county of Cook and State of Illinois, have invented an Improvement in Lifting-Jacks, of which the following is a specification:

The nature of this invention relates to a certain new and useful improvement in liftingjaeks; and its object is to provide an easy, efri cacious, and economical device for securing the lifting-lever in position.

Figure l is a side elevation of my device. Fig. 2 is a top plan. Fig. 3 is an enlarged sectional elevation. Fig. 4 is an enlarged crosssection through the cam.

Like letters refer to like parts in each figure.

In the accompanying drawings, A A represent the folding legs of the jack, pivoted at top, one to each side of the lifting-lever B, as shown, extended for use. A brace, C, is pivoted at one end to the leg A, and its free end is provided with a yoke, D, Which embraces the lifting-lever, and between the ends of this yoke, which project above said lever, is journaled the cam E.

It will readily be seen that, by means of the brace, yoke, and cam, the lifting-lever may be securely fastened in any desired position.

The operation of this device is so simple that any further description thereof is deemed unnecessary for the purposes of this specification.

I disclaim any part of the invention shown in the patents of A. M. Culver, dated February 19, 1867, February 18, 1868, J T. Hamilton and E. F. Conner, dated March 19, 1872, and November 25, 1873; but What I do claim as my invention, and desire to secure by Letters Patent, is-

l. In lifting-jacks, the cam E, in combinatioli with a brace, C, provided With a yoke, D, for

the purpose of securing the lifting-lever B in 

